Portable heater



FIG. 1 is a right side front perspective view of a portable heater showing my new design;

FIG. 2 is a left side rear perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a rear elevation view thereof; and,

FIG. 7 is a top plan view thereof.

The broken line showing of a front top grill, front bottom grill and top front control are included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for a portable heater, as shown and described. 